Samsung Freezer not cold enough after power cut

[newbuyer17]

We have a Samsung RSG5UCRS american style fridge freezer.
We had a power cut earlier in the week, and since then food isn't freezing.

I can hear the fan working. The setting for the freezer is showing -25 degrees which is the temperature you want it to be, and when I open the door it stays on -25, which I believe indicates that is the temperature it actually is.

However, it isn't freezing. I threw out all of the ice cubes last night, and it has only madew about 6 since. It would usually have filled the bucket again.

Now for the interesting bit. If I power it off and then back on. The desired temperature is -25 again. But if I open the door, the actual temperature is only -4. I leave it 30 mins, and the temp has gone colder to -6, so it looks better. But leaving longer its back to desired -25, actual 25. If I then power it off, the actual is actually -4 again, not -25.

So it seems like it thinks it is colder than it is, and stops trying. Unless it really is trying and just can't get the temp down.

As I say, this has all been since a power cut on Monday.

Is there anything that is obviously damaged? Or is it possible something could have become blocked whilst the power was off (around 8 hours, but we never opened the door once)

Thanks in Advance

 

[newbuyer17]

Further info.
I've had it apart.

I found the thermostat in the top of the freezer. I tried warming this with a lighter to see if I could make it change temperature, and it didn't want to. Still reading -25 degrees C. It was warming up slightly, but then I had the door open. So perhaps it was working, but just takes a long time to register to avoid swinging back and forth. So perhaps this is working correctly.

I also tried disconnecting it completely, which produced a fault.

From the front, I removed the panel behind the shelves. There was a fan inside there which never came on. There was a tiny bit of ice on the cooling fins, but very slight, I do not think that is the issue.

I then took the lower rear panel off behind. Lots of dust which I hoovered.

However at no point did the fan or compressor come on. I even restarted it to see what happens. It kinda clicks a little then does nothing.

Here is a video of it being powered on at the mains:

https://drive.google.com/file/d/1-t_pu2oriUG3aBWjz-NUoE4aI7wETX2B/view?usp=sharing

The temperature guage on the front now shows 9 degrees, yet the freezer isn't powering up, so despite my earlier reservations I think the thermostat is probably OK, and its something else preventing it from actualy cooling.

Any ideas, or could it be too many things?

Thanks in advance.